


Loving Father, Grateful Sons

by SoloShikigami



Category: Undertale (Video Game)
Genre: Bondage, Daddy Kink, Incest, M/M, Multi, Threesome - M/M/M
Language: English
Status: Completed
Published: 2020-05-12
Updated: 2020-05-12
Packaged: 2021-03-02 19:41:34
Rating: Mature
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 2,206
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/24152239
Author URL: https://archiveofourown.org/users/SoloShikigami/pseuds/SoloShikigami
Summary: Gaster noticed that sometimes Sans has a difficult time being nice to himself, so he recruits Papyrus to remind Sans how much he is loved, appreciated, and deserves to be so.
Relationships: W. D. Gaster/Papyrus/Sans
Comments: 1
Kudos: 53





	Loving Father, Grateful Sons

**Author's Note:**

> Written for PancakeUniverse in November, 2018!

“You’re panting, Sans,” Gaster murmured. “I guess this means that Papyrus is doing a good job?”

Sans fought back a whimper, looking down at his brother, who was kneeling between his legs, humming in enjoyment at his task of pleasing his cock.

Gaster stroked Sans’ skull, one arm wrapped around his waist, helping to hold him still and steady on his lap.

“G-gaster,” Sans gasped, leaning back into the tall scientist. “C-c’mon, enough, please!”

“Mmm, I don’t think so, Sans,” Gaster murmured, his hand wandering down to stroke Sans’ ribs over his t-shirt. “You seem to have a difficult time taking the pleasure that we enjoy giving you; you feel unworthy of it, undeserving, and what kind of father would I be if I let you think that?”

Sans tried to squirm, but with his arms tightly bound from wrist to elbow behind his back, his legs each hanging over Gaster’s to keep them apart, he had absolutely no leverage.

“You always were stubborn and obstinate,” Gaster said with a slightly exasperated sigh. “Even too stubborn to take a compliment.”

“Yes, he never has taken praise particularly well,” Papyrus said, giving his mouth a moment to rest, pumping Sans slowly with his hand. “For a while I had lamented on his laziness, hoping it would fuel some sort of fire within him. Of course, that was before I found a different fire to stoke.”

Sans opened his mouth to speak, but his words were lost as Papyrus went down on him again.

Gaster sighed, hugging Sans firmly, leaning down to press gentle kisses along his neck. Before he was able to return from The Void, his creations never realized that they could be intimate with each other; both of them laboring under false pretenses that their feelings for each other were wrong and could never be realized. Gaster took the full blame on that and did all he could to assure his sons that they were free to love whoever they wanted, even if it was each other. He soon became someone for both of them to love as well, and he didn’t mind in the least.

Sans was more hesitant with his affections, rarely told either of them what he wanted, and tended to take care of the needs and wants of his lovers before, or instead of, his own. Sometimes he needed a touch more persuading, and as much as he fought against it, he had expressed that he enjoyed it and promised to use a safe word if he really did not wish for intimacy.

So far, that safe word had not been uttered.

“I know Papyrus has said how lazy you were while I was gone, but running a sentry station, several of them in fact, and a hot dog stand is hardly laziness,” Gaster said, kissing Sans’ neck and cheekbones gently as he spoke.

“Like it’s hard to sit in one place and sell water sausages on buns,” Sans grunted, shuddering at the attentions he was given.

“And ever since I have come home, you have been working overtime. I think you ought to be a little nicer to yourself, or at least, allow us to be nice to you.”

Sans moaned as Papyrus hummed around him, Gaster’s hips hitched up slightly, the growing bulge brushing against Sans’ tailbone. Papyrus pulled off the thick, blue cock slowly, then he got to his feet, pressing himself against Sans as he leaned up to kiss him deeply.

“Please let us make love to you, Sans,” Papyrus pleaded, climbing into Sans’ lap, his wet slit sliding against his cock. “I want to make you feel good.”

“You always do,” Sans’ murmured, feeling his head spinning slightly.

“I’d like to help as well,” Gaster said, wrapping his arms around them both, pulling Papyrus in closer, making their sexes grind against each other.

Sans moaned, low and long, his head falling back on Gaster’s shoulder.

“Please, please, I can’t take it anymore,” Sans panted. “You both are horribly convincing.”

Gaster chuckled, rocking his boys, making them mewl in want.

“My sweet, sweet boys,” Gaster murmured. “Papyrus, would you mind helping Sans and I get ready?”

Eager to help as always, Papyrus slid off Sans’s lap, dropping to his knees again, licking the head of Sans’ dick like a lollipop and a hand slid under him, searching for his tight entrance. Sans squirmed again, but Gaster moved his hands to his pelvis to hold him still. Sans cried out when Papyrus found his prize, carefully twisted a finger into him, moving slowly as to not hurt him.

“Mmm, magnificent, the both of you,” Gaster murmured. “Papyrus, your eagerness is absolutely arousing, willing to do anything to help; I bet he’s being ever so gentle with you, isn’t he, Sans?”

Sans bit back a whimper, his legs kicked weakly, then settling into shallow panting as Papyrus’ finger started moving in and out of him.

“Answer your father, Sans,” Gaster said, his left hand slipping up to grip his jaw firmly. “Is Papyrus being gentle with you?”

“Ye-yeah,” Sans whispered.

“No, answer me properly.”

“Y-y-yes, s-sir,” Sans groaned, trying to move out of the grip and curl into himself, but he simply couldn’t.

“Such a good boy,” Gaster praised, turning Sans’ face towards him, intending to kiss him gently, but was happily surprised when Sans pressed into him, desperate for something that he couldn’t articulate.

Papyrus continued to prep Sans, lapping at his cock, his other hand working further back to the waistband of his father’s pants; his nimble fingers had no problem undoing the one button and coaxing the zipper down. Thankfully, Gaster never wore underwear, so pulling out the thick rod of purple magic wasn’t difficult either. Above him, he heard Gaster sigh into Sans’ mouth, and Sans continued to make needy sounds. Smiling, Papyrus stroked Gaster’s cock, moving to slip a second finger into Sans, listening to the lovely sounds above him and trying very hard to ignore his own dripping pussy that was eager to be touched as well.

“Mmmph,” Sans whined, pulling away from Gaster with a gasp. “I, I can’t take anymore.”

“You aren’t very well prepared,” Papyrus warned, though he began scissoring his fingers, knowing that Sans likely would say he didn’t care or mind.

“I don’t care!”

Right on cue.

“Sans, your little brother has a point,” Gaster said.

“Gaster, please, I c-can’t anymore!” Sans cried, struggling again against his bonds.

“Mmm, I don’t know.”

“Please, Daddy?’ Sans said, looking up at him, his eyes pleading as much as his words.

Gaster had a horrible weakness for his eldest calling him by a parental designation, and while he was certain Sans knew it and used it to his advantage, this was a situation that Gaster couldn’t ever deny him what he wanted.

“Fuck,” Gaster breathed. “Papyrus, if your brother insists on moving forward, we really shouldn’t deny him.”

“As you wish, Father,” Papyrus said with a sigh, gently taking his hands out from underneath Sans and standing back up.

“Hmm, I think we shouldn’t be making you wait much longer, either, my dear boy,” Gaster said, reaching forward with one hand to trace a finger through his glistening slit.

“Nyeh, th-thank you, that w-would be nice,” Papyrus admitted with a pleased shudder.

Gaster and San were sitting in a fairly low chair, and with Papyrus’ height, it didn’t take much for him to move in close, lifting a leg and positioning himself over Sans as Gaster adjusted his eldest in his lap.

“D-dad should go in first,” Sans pointed out.

“Shush,” Gaster said, though he knew he was right, and concentrated more on lining his cock up with Sans’ entrance. “Just breathe, son.”

Gaster tried to take his own advice as he breached the entrance of his eldest creation. He usually didn’t have intercourse with Sans, he mostly watched his two creations play and pleasure one another, sometimes when Papyrus was feeling particularly needy and Sans was working, he would assist him, but this was still a very, very rare treat. Sans was tight, still mostly uncharted territory, and his reactions to being filled were exquisite. Once he was seated fully in Gaster’s lap, Gaster stilled, holding him tightly, murmuring praises into his neck.

“You both look so good right now,” Papyrus whispered, enchanted by the sight.

“Pap, please, I need you,” Sans begged.

“Go ahead, Papyrus,” Gaster murmured.

With a bright grin, Papyrus moved in more, putting his hands on Sans’s shoulders to steady himself, rubbing his wet pussy over Sans’ cock teasingly.

“Papyrus!” Sans cried.

“Papyrus don’t tease your brother,” Gaster said, his eyes flashing up at him.

Papyrus giggled a little before settling over his brother, sighing in satisfaction as he settled into his lap. They both moved slowly with Sans between them, working out a rhythm that suited them all. Sans mostly went still, only moved by his creator and his brother, tears slowly beginning to fall from his blank eye-sockets, small moans and whimpers being the only sounds he could muster for a while. Once Gaster and Papyrus began to move in tandem, Sans was hoping they would move faster as he felt ready to burst, but they continued to move slowly, gently, and while Sans enjoyed his position of doing pretty much nothing, he knew he was being driven absolutely crazy.

“Ooohhh, fuck,” Sans moaned. “Please, you guys, just fuck my brains out already!”

“Oh?” Gaster said. “Is that what you want? You want your father and your sweet little brother to make you cum?”

“Please, please, I need to,” Sans begged.

“First, I want you to promise us that you will try harder to think a little higher of yourself, Sans,” Gaster said. “Listen to your brother when he tells you about your good qualities, let us love you the way you love us, and stop being so hard on yourself.”

“I promise, I promise, just, please!” Sans said, trying to move but finding it impossible to now.

“That doesn’t sound sincere,” Gaster said flatly. He thrust up hard, drawing a borderline scream from Sans. “I want you to look Papyrus in the eye and promise. A proper monster says what he means and means what he says.”

Sans opened his eyes and looked into Papyrus’. Papyrus was smiling encouragingly, though Sans knew Papyrus was being a bit of a brat, contracting his magic around his cock in waves to entice him. But Sans could also find fault with Gaster, specifically putting him in this position to coerce a promise from him, despite knowing how Sans felt about promises.

But this was a little different, wasn’t it? Gaster really did want what was best for him, and for Papyrus, too. Papyrus most definitely wanted what was best for Sans, so when his little brother looked at him with that sweet smile, how could Sans not?

“I pr-promise,” he whispered. “I promise, Papyrus, I’ll do better.”

“Nyeh, heh, heh, I know you will, brother,” Papyrus said, leaning in to kiss Sans, slowly, deeply.

“My good, sweet boys,” Gaster said, leaning down to kiss the back of Sans’ neck. “I think he deserves a reward for being such a good boy, eh, Papyrus?”

“Yes, Father,” Papyrus said once he broke off the kiss.

Gaster reached around to grip Papyrus’ hips and with all his strength, he thrust his hips up into Sans, pulling Papyrus into him as well. The two cried out at the force of it but moved back into it. Papyrus braced a foot on the floor, and Sans could only be at the mercy of them both.

“Fuck, you feel so fucking good, Sans,” Gaster growled, releasing Papyrus so he could grip onto Sans tightly, fucking mercilessly into him. “So tight, hugging my cock just right, it’s a shame we don’t do this very often.”

“Sans,” Papyrus whined above him, impaling himself on his cock over and over. “You’re so big, you feel so good for me, too.”

Sans felt lost in a haze of movement and pleasure, his voice cracked, strained from moaning, resigning himself to being no more as a vessel, a toy for his brother and father to please themselves with – and he had to admit, it wasn’t too bad of a position to be in.

But all wonderful things come to their conclusions, and without warning, Sans came with a strained shout, Papyrus not too far behind him as he gasped and wrapped his arms tightly around his brother, crying out his name as he gushed in Sans’ lap. The fluids dripped down to where Gaster and Sans were joined, aiding Gaster in coming to his own peak, releasing inside of Sans with a grunt, a moan, and finally a sigh.

Gaster rested his head on Sans’ shoulder, Papyrus cradling his brother’s skull as he kissed him, murmuring gratitudes. Sans fell back into Gaster with a sigh, his eyes closing as his breathing slowed.

“I think we need to make love to Sans more often,” Papyrus murmured.

“I would love to,” Gaster said.

A small, quiet string of unintelligible murmuring slipped from Sans’ mouth.

“Heh, but we will discuss this later. I do believe a shower is in order.”

**Author's Note:**

> Like what you read? Please check out my social media for more fun!  
> [ My Tumblr](https://soloshikigami.tumblr.com/)  
> [ My Twitter](https://twitter.com/SoloShikigami)


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